Gradkowski originally suffered the separation on Sept. 26 against Arizona, causing him to miss four weeks. He re-aggravated the injury on Oct. 10 and hadn't started after that until last weekend against Miami. The latest injury includes other damage, but the separation is the worst of it.

This will end a tumultuous stint under center for the Raiders, where a reported difference in opinion between the coaching staff and front office led to a back-and-forth game between Gradkowski and Jason Campbell as starter. Tom Cable has already ruled out giving No. 3 Kyle Boller a chance, so the team is Campbell's from now on.

Among starting NFL quarterbacks, Campbell is 28th out of 33 in passer rating, while Gradkowski is 32nd.